How much more dense is platinum than gold, in grams per cubic centimeters

2,2 g/cm^3

Explanation:

According to your table, the platinum has 21,5 g/cm^3, and gold 19,3 g/cm^3

Doing the diference:

Porcentual expression:

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).